Nokia RM-57 Service Manual page 183

Nokia 6681/6682 mobile terminal

Table of Contents

RM-57/58

RF Troubleshooting and Manual Tuning Guide

Introduction to RF troubleshooting..........................................................................................................................................7-5

RF key component placement.....................................................................................................................................................7-5

Fault finding test point locations...............................................................................................................................................7-7

Receiver troubleshooting...........................................................................................................................................................7-10

Introduction to Rx troubleshooting..................................................................................................................................7-10

GSM Rx chain activation for manual measurements / GSM RSSI measurement.................................................7-10

Transmitter troubleshooting....................................................................................................................................................7-11

General instructions for Tx troubleshooting..................................................................................................................7-11

Checking GSM and Bluetooth antenna functionality...................................................................................................7-13

RF tuning.........................................................................................................................................................................................7-14

Introduction to RF tunings...................................................................................................................................................7-14

RF autotuning .........................................................................................................................................................................7-14

RF manual tuning guide.......................................................................................................................................................7-18

Required manual tunings after component changes...........................................................................................7-18

RF channel filter calibration...........................................................................................................................................7-19

Temperature sensor calibration .................................................................................................................................7-19

Receiver tunings................................................................................................................................................................7-20

Rx calibration ..............................................................................................................................................................7-20

Rx band filter response compensation ...............................................................................................................7-24

Rx AM suppression .....................................................................................................................................................7-29

Transmitter tunings.........................................................................................................................................................7-30

Tx IQ tuning .................................................................................................................................................................7-30

Tx power level tuning ...............................................................................................................................................7-33

List of Tables

Table 13 RF channel filter calibration tuning limits..........................................................................................................7-19

Table 14 Temperature sensor calibration tuning limits..................................................................................................7-20

Table 15 RF tuning limits in Rx calibration...........................................................................................................................7-23

Table 16 RSSI level values..........................................................................................................................................................7-30

List of Figures

Figure 61 RF key component placement.................................................................................................................................7-6

Figure 62 Test point locations for spectrum analyzer.........................................................................................................7-7

Figure 63 Test points for oscilloscope - bottom....................................................................................................................7-8

Figure 64 Test points for oscilloscope - top............................................................................................................................7-9

Figure 65 RSSI Reading window..............................................................................................................................................7-10

Figure 66 RF Controls window..................................................................................................................................................7-13

Figure 67 Feed and GND spots of the main antenna.........................................................................................................7-13

Figure 68 BT antenna..................................................................................................................................................................7-14

Figure 69 RF channel filter calibration typical values.......................................................................................................7-19

Issue 1

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Company Confidential

Nokia Customer Care

Page 7-3

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